Depression linked to harmful fats in Western diet

Consuming harmful fats that are prevalent in a Western diet is linked to higher rates of depression.

Findings from researchers show trans-fats and saturated fats consumed in larger quantities boosts the risk of depression even further. In their study, the scientists also found olive oil consumption seems to protect from depression.

The researchers studied 12,059 volunteers who were part of the SUN project, over a period of 6 years. They found polyunsaturated fats, found in fish, vegetables oils and olive oil was associated with a 48 percent reduced risk of suffering from depression.

In the six-year study, the participant’s lifestyle, symptoms and dietary intake were tracked. None of the volunteers suffered from depression at the beginning of the study.

At the end of the six-year period, 657 subjects developed depression that the researchers say was also "dose dependent". Individuals who consumed the most trans-fats and saturated fats from industrially-produced pastries and fast food had the highest risk of becoming depression, something the researchers say might also share a link with inflammation that promotes cardiovascular disease.

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According to Almudena Sánchez-Villegas, Associate Professor of Preventive Medicine at the University of Las Palmas de Gran Canaria, lead author of the study, "...the more trans-fats (that) were consumed, the greater the harmful effect they produced in the volunteers."

The authors suggest rising rates of depression worldwide parallel higher per capita income and a shift toward processed and prepackaged foods and a poor diet.

Almudena Sánchez Villegas says higher rates of depression can be traced "to radical changes in the sources of fats consumed in Western diets, where we have substituted certain types of beneficial fats—polyunsaturated and monounsaturated in nuts, vegetable oils and fish—for the saturated and trans-fats found in meats, butter and other products such as mass-produced pastries and fast food".

Even though the study was performed in a population whose consumption of trans-fats accounts for 0.4% of total energy intake, Miguel Ángel Martínez-González, Professor of Preventive Medicine at the University of Navarra who directed the study said, "we derive the importance of taking this effect into account in countries like the U.S., where the percentage of energy derived from these foots is around 2.5%."

The scientists note the findings also correlate with lower rates of depression seen in countries where a Mediterranean diet prevails. Previous research from the scientists also found a lower risk of depression from eating a Mediterranean diet, published last year in the Archives of General Psychiatry.

The researchers say a poor diet is shown in the study to contribute to higher rates of depression. Foods typically consumed in a Western diet that contains trans-fats and saturated fats should be considered harmful. The scientists say the same mechanisms that contribute to heart disease, and associated with a poor diet, may also be contributing to increased rates of depression.